lintian
Debian package. With Lintian version
0.3.0, you don't need a configuration file in order to check packages.
$ lintian libc5_5.4.38-1.deb E: libc5: old-fsf-address-in-copyright-file W: libc5: shlib-without-dependency-information usr/lib/libgnumalloc.so.5.4.38 W: libc5: shlib-without-dependency-information lib/libc.so.5.4.38 W: libc5: shlib-without-dependency-information lib/libm.so.5.0.9 E: libc5: shlib-with-executable-bit lib/libc.so.5.4.38 0755 E: libc5: shlib-with-executable-bit lib/libm.so.5.0.9 0755 E: libc5: shlib-missing-in-control-file libgnumalloc usr/lib/libgnumalloc.so.5.4.38 $As you can see, Lintian uses a special format for all its error and warning messages. With that, its very easy to write other programs which run Lintian and interpret the displayed messages.
Depending on which tag has been reported, the line may contain additional arguments which tell you, for example, which files are involved.
If you should not know what a certain tag is about, you can specify the -i option when calling Lintian to get a detailed description of the reported tags:
$ lintian -i libc5_5.4.38-1.deb E: libc5: old-fsf-address-in-copyright-file N: N: The /usr/doc/<pkg>/copyright file refers to the old postal address of N: the Free Software Foundation (FSF). The new address is: N: N: Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, N: MA 02111-1307, USA. N: [...] $In some cases, the messages contain some additional text with a leading hash character (#). This text should be ignored by any other programs which interpret Lintian's output because it doesn't follow a unique format between different messages and it's only meant as additional information for the maintainer.
In the first case (where Lintian has a bug) you should send a bug report to the Debian bug tracking system and describe which package you checked, which messages have been displayed, and why you think Lintian has a bug. Best would be, if you would run Lintian again over your packages using the -d option, which will cause Lintian to output much more information (debugging info), and include these messages in your bug report. This will simplify the debugging process of the authors of Lintian.
In the other two cases (where the error is actually an exception to policy) you should contact the Lintian maintainers too, including the Lintian error message and a short note, why you think this is an exception. If the Lintian maintainers agree that this is a valid exception, they'll add the message to Lintian's global overrides file. With that, Lintian will know about this exception and not report the problem again when checking your package. (Actually, Lintian will report the problem again, but with type overridden, see above.)